1. Technical Field
The present invention relates to a data driving circuit, an organic light emitting diode display using the same, and a method of driving the organic light emitting diode display, and more particularly, to a data driving circuit for displaying an image with desired brightness, an organic light emitting diode display using the same, and a method of driving the organic light emitting diode display.
2. Related Art
Various flat panel displays have recently been developed as alternatives to the relatively heavy and bulky cathode ray tube (CRT) display. Flat panel displays include a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an organic light emitting diode display (OLED), etc.
Among the flat panel displays, the organic light emitting diode display can emit light for itself by electron-hole recombination. Such an organic light emitting diode display has advantages in that response time is relatively fast and power consumption is relatively low. Generally, the organic light emitting diode display employs a transistor provided in each pixel for supplying current corresponding to a data signal to a light emitting device, thereby causing the light emitting device to emit light.
An organic light emitting diode display comprises a pixel portion including a plurality of pixels formed in a region defined by intersection of scan lines and data lines, a scan driver for driving the scan lines, a data driver for driving the data lines, and a timing controller for controlling the scan driver and the data driver.
The timing controller generates a data control signal and a scan control signal corresponding to an external synchronization signal. The data control signal and the scan control signal are supplied from the timing controller to the data driver and the scan driver, respectively. Furthermore, the timing controller supplies external data to the data driver.
The scan driver receives the scan control signal from the timing controller. The scan driver generates scan signals on the basis of the scan control signal and supplies the scan signals to the scan lines.
The data driver receives the data control signal from the timing controller. The data driver generates data signals on the basis of the data control signal and supplies the data signals to the data lines while synchronizing with the scan signals.
The display portion receives first power and second power from an external power source, and supplies them to the respective pixels. When the first power and the second power are applied to the pixels, each pixel controls a current corresponding to the data signal to flow from a first power line to a second power line via the light emitting device, thereby emitting light corresponding to the data signal.
That is, in the organic light emitting diode display, each pixel emits light with a predetermined brightness corresponding to the data signal, but cannot emit light with desired brightness because transistors provided in the respective pixels are different in threshold voltage from each other. Furthermore, in the organic light emitting diode display, there is no method of measuring and controlling a real current flowing in each pixel in correspondence to the data signal.